Baseline Immune Signatures in Serum Extracellular Vesicles Distinguish Food-Induced from Wheat-Dependent Exercise-Induced Anaphylaxis.

Food-induced anaphylaxis (FIA) is a life-threatening allergic reaction, while wheat-dependent exercise-induced anaphylaxis (WDEIA) is triggered by wheat ingestion plus cofactors. To elucidate their differences, we profiled serum extracellular vesicle (EV) proteomes from 240 participants, including WDEIA, FIA, oral allergy syndrome (OAS), and healthy controls. All blood samples were obtained at least one month after the most recent acute allergic reaction, using TMT-based LC-MS/MS with ELISA validation. A total of 583 EV proteins were confidently identified, revealing distinct immune features. Compared with controls, EV-derived C1-inhibitor (C1-INH) significantly decreased in both WDEIA and FIA, showing diagnostic potential for systemic anaphylaxis. Seventy-six proteins differed between WDEIA and FIA, with reduced apolipoprotein E (APOE) in FIA and elevated eosinophil cationic protein (ECP) in WDEIA, both exhibiting good discriminatory power. These findings indicate that serum EV proteomics can reveal unique immune signatures and identify C1-INH, APOE, and ECP as potential biomarkers distinguishing food-related anaphylaxis subtypes.